US Secretary of State Rex Tillerson said on Tuesday that Turkey’s military operation in the Syrian district of Afrin is hampering the US-led coalition’s efforts to maintain the focus on the fight against the Islamic State of Iraq and the Levant (ISIL) in Syria.

“As to the situation in Afrin, it has detracted from our fight to defeat ISIL in eastern Syria,” Tillerson said at a joint press conference in Kuwait with Foreign Minister Sheikh Sabah al-Khalid al-Sabah. He said part of the YPG was moving toward Afrin to fight against Turkish forces and this situation affects the fight against ISIL and Washington wants to make sure Turkey is aware of this.

Tillerson is heading the US delegation to the ministerial meeting of the Global Coalition to Defeat ISIL hosted by Kuwait. The secretary of state’s itinerary includes a stop in Turkey, where he will meet with senior Turkish officials to discuss a range of bilateral and regional issues.

US Director of National Intelligence Daniel Coats has also expressed concern on Tuesday over Turkey’s ongoing military operation in Syria. Speaking at a Senate Intelligence Committee hearing on worldwide threats, Coats said “Operation Olive Branch” “increases” risk to the US forces in the area. He said Turkey will seek to thwart “Kurdish ambitions” in the Middle East and claimed its current operation is “complicating” ongoing counter-ISIL activities in the region.

However, at odds with Pentagon policy Coats has called the YPG as the Syrian militia force of the terrorist PKK. In a Worldwide Threat Assessment Report submitted to the US Congress, Coats called the YPG “the Syrian militia” of the terrorist PKK, warning that it will probably “seek some form of autonomy but will face resistance from Russia, Iran, and Turkey.”

Meanwhile, US State Department Spokeswoman Heather Nauert said on Tuesday that Tillerson’s planned visit to Turkey on Thursday shows just how “serious this matter is,” by referring to the stark differences in Turkish and US interests in Syria during the daily briefing. “This is one of the areas of deep, deep concern on the part of the administration and the US government,” Nauert told reporters in Washington D.C. “We certainly don’t want to see violence to further escalate,” she said.

Tillerson is set to visit the NATO ally bordering the Middle East with Syria on the agenda. Recently, the two countries have been on board an escalating tension over the US support given to the People’s Protection Units (YPG). Turkey has been enraged by US support for the YPG, which Ankara sees as a terrorist organization and an extension of the outlawed Kurdistan Workers’ Party (PKK) that has been waging an insurgency on Turkish soil for over 30 years. Washington has backed the YPG in the fight against the ISIL in Syria.

Turkish General Staff has announced on Wednesday that at least 1,485 PYD/PKK and allegedly ISIL militants have been “neutralized” since the beginning of Operation Olive Branch in Syria’s Afrin. Turkish authorities often use the word “neutralized” in their statements to imply the militants in question either surrendered or were killed or captured. In the statement, the military said Turkish Armed Forces had “neutralized” 46 more PYD/PKK and alleged ISIL militants in airstrikes that were carried out overnight.

Turkey last month launched an incursion into Syria, which it calls “Operation Olive Branch,” to sweep the YPG from its southern border. It has also threatened to press on to Manbij – currently under the control of a YPG-led force – and has warned American troops stationed there not to get in the way. American troops would remain in the northern Syrian town of Manbij despite Ankara’s demands for a US pullout, the top US general in the coalition fighting ISIL pledged on Feb. 7.